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Does Rolls Royce produce any engine that matches the capabilities of the GE9x?
Does Rolls Royce produce any engine that matches the capabilities of the GE9x?
If not, does Rolls Royce have any public plans for such an engine in the future?

Interesting question. Do you mean a specific competitor in terms of installment on a specific plane, such as the 787 or just one in general that was made as a response? Different applications would consider different engines/variants of an engine.

It seems that RR does not have a portfolio to match the capabilities of GE9x. That is why I am asking this question. Is Rolls Royce losing out in the technological advancement?

Which "capabilities" are you talking about specifically? Thrust output? Size? Fuel Efficiency? Cost? Weight?

Thrust output and fuel efficiency in particular. GE marketing indicates that GE9x is 10% more efficient than its predecessor and with a 470KN of takeoff thrust.
It is really hard to compare apple to apple with such little data. But Trent XWB is clearly losing in terms of thrust.

But the Trent 1000 or 7000 are designed for 787 or a350 or a330 Neo. Not for 777x which is bigger. It is totally incomparable.

@TayWeeWen I don’t think they design engines without an application in mind, so without access to the 777X, why would they need one?

@TayWeeWen These aren't fighter aircraft. The more thrust you put in, the more drag and more fuel use you'll have in cruise. There's no need to "match" someone in thrust. RR's three-spools do compete in the same market and have room for growth.

@Therac what these companies actually compete in technologically is the thrust per/drag and thus fuel economy. With more thrust per square unit of surface area companies can reduce fuel consumption by reducing drag, and with enough advancement, be able to reduce the number of engines necessary to move the aircraft, further improving efficiency. What I'm trying to say is that the name of the game is efficiency, and thrust increase without increasing other negative factors (drag, size, weight) is a viable and much pursued area of technological development.

@Jihyun Thrust increase without increasing any of drag, size, weight, and you forgot the big one - SFOC - is insanely difficult to achieve and sustained gains in that are around a percentage point per new design. Current efficiency improvements are primarily driven by increasing the BPR by mounting larger fans, increasing the OPR to drive these fans without considerably enlarging the core, and using tech advances to avoid substantial weight increase while doing that. Drag and size grow.

@Jihyun that is what I wanted to communicated. The advance in thrust without increase of weight reduces drag, in addition of reducing structural requirement of aircraft. That is one reason 777 9X being a heavier aluminium plane can be competitive against composite structure like A350-10000.
Another reason is because of engine efficiency itself.

… @Therac this is why these engines are considered great advancements. The OP was asking about parallel development, and these are the factors that impact it. Saying that you absolutely can't get a significant improvement in one without a crippling drawback in another is just wrong. Sometimes sacrifices are made, but in two competing models for a SPECIFIC job, the advancements are made however slowly but they are there. Your original comment wasn't referring to models competing in the same niche. Of course many engines compete in the same market, but not all for a specific segment.

@Jihyun The GE9x is a 340cm fan, Trent XWB a 300cm fan engine. It's quite expected that a larger engine will produce more thrust. Of course the GE9x is more advanced, but "more thrust" just isn't the way I'd put it.

@Therac I know, what I'm saying is that significant thrust increase doesn't always mean significant increase in drag/fuel consumption, which would mean an overall more efficient engine right? THAT'S what these companies compete over, the overall advancement of their engines respective to the niche they're trying to fill is the real comparison, NOT singular data points like drag(a) vs. drag(b). A narrow view like that will pretty much lead you to one conclusion: that engines have become much larger and induce much more drag than in the past. Which I'm sure is a very difficult view to support.

[Extension] I'm not trying to change how you see the industry and your opinions on planes, but trying to argue a point on a spec A vs spec B basis limits your argument to data analysis that ignores the big picture. There are man examples where the lab data (especially where better numbers for some specs leads to a detriment in the overall performance of a machine) just doesn't support the field experience. Case in point, the exclusion of a cannon in the early Phantoms in Vietnam, or the whole 1911 v. Beretta M9 debate (I can tell you from experience that the M9 is plain garbage)

I should have define more clear, each generation of jet engine is an improvement in thrust vs weight ratio, as well as fuel economy.  Nevermind one change the diameter of the engine, the Thrust vs Weight ratio of that spatial dimension remain more or less unchange for that family and their derivative.

After some research, I believe RR Ultrafan is the answer to GE9x. At this point of time, there is too little information for comparison.
GE9x is one generation ahead of Trent XWB. As per now, the development (bug fixed) is still on going.
That partly explains that despite 777x being overwhelmingly heavier than A350, it is still competitive at the 400 passengers segment on the 777-9 platform.
Nevertheless the A350 frame could have more potential. By 2025 upon the release of RR Ultrafan (or if it is possible to design with a GE9x based derivative), Airbus could easily do a A350Neo, which could easily be the most efficient plane in the market.

You still seem to be making a false assumption that RR need “an answer” to the GE 9x, which means an engine with the same thrust output. They don’t. They don’t need to make a good engine for an aircraft they have not won a contract to supply with an engine. They need to make good engines for the aircraft they have won a contract on. These are not the 777x, so, their engines are optimised for those aircraft instead.

It is understood that the top 3 engine maker could meet the thrust specification of Boeing and Airbus as long as they scale the diameter. But engine of generational difference can provide a higher thrust vs weight ratio on top of higher fuel efficiency. Then these engine makers will scale up or down the thrust base on the requirement of commercial aircraft maker. I dont think I have to explicitly explain that. Without competition why would RR invest money on Ultrafan and PW on GTF. GE9x will eat their lunch if they just sit by.

First let's talk about thrust.  Jet engines are designed for very specific thrusts for every specific applications.  For example, look at the GEnx-1B versus the GEnx-2B.  The Boeing 787-8 has GEnx-1B engines rated for ~70k lbf takeoff thrust.  At about the same time as Boeing was developing 787-8, it was also developing the 747-8.  That plane needed slightly less thrust per engine, about 5% less. Boeing could have just put the GEnx-1B on that plane.  But they didn't. Instead they had GE develop the GEnx-2B, rated for 66.5k lbf thrust.  They did that because an engine that had five percent too much thrust was a completely unfeasible option.  The GEnx-2B is smaller and several hundred pounds lighter.  So my point here is that RR is never going to develop an engine the size of the GE9X unless they have a very specific contract for a plane that needs exactly that much thrust.  Every engine RR makes is going to be sized exactly as big as it needs to be and no bigger.
RR certainly could make an engine that big if they had a contract to do so.  If you know how to make an engine that produces 70klbf of thrust, you know how to make an engine that produces 100 klbf of thrust.  Just make everything a little bit bigger. Turbomachinery is not perfectly scaleable, so just because you know how to make an engine with 100 lbf of thrust does not mean you know how to make an engine with 100,000 lbf of thrust.  But from 70k to 100k is not a big leap. Definitely within their capability.
As for everything else, I'd say just look at the market share. There's some interesting statistics here.  http://www.alafco-kw.com/upload/Media_Library__March_2016____Aircraft_Market_Report__March_2016__921.pdf
For example: RR has 59% of the A330 market, a plane on which there are 3 different engine options available (GE, RR, P&W).  RR is certainly behind GE on the 787, but not by a lot.  And RR has an exclusive contract on the A350.  Overall RR is competitive in the market versus the other manufacturers. If RR was "losing out in the technological advancement", you would see this reflected in their market share, but this is not what is happening.

Regarding the GEnx-2B. I always assumed, that the usage of bleed air for air conditioning - and not only anti-icing - is the major reason for the differences? And the other changes are minor optimizations for 747-8 and side-effects.

Certainly the bleed air versus electrical generators is a difference, but really the generators extract about the same amount of power as the bleed air.  So if you took at GEnx-1B and put a bleed system on it, you'd still basically have 70k thrust. Maybe a little different, but not 5%. The 5% thrust difference is mostly from scaling the fan diameter down.


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Does a wing produce an appreciable amount of lift during the takeoff roll prior to rotation?
I was hoping for some insight on this, perhaps also from pilots who have used AOA indicators. This because I assume that an AOA indicator is the only means to get at least an idea of how much lift is being produced.
The real question: In a crosswind, during the roll, it is friction from the tyres that keeps the aircraft tracking down the runway, since you can't crab before becoming airborne. If the wing starts to produce lift during the takeoff roll, that friction will reduce.
Is that lift significant, or is it minimal (on a tricycle-gear aircraft)? In other words, does the surface friction decrease by lots, or is it relatively unaffected throughout the ground roll?
As a follow-on, how does ground effect influence the lift that is generated during ground roll at essentially a fixed AOA until rotation?
I'm interested primarily in the business jet side of the house, takeoff weights between 20 and 35 tons, but would also like to know what the answers might be for airliners (Airbus, Boeing). I was going to exclude the aircraft that - with all due respect - "sit funny" on the ground  such as the CRJ900 or the G280, but then thought that fuselage attitude might not be directly related to AOA.

Don't business jets often have a design that puts the wing at a slight negative angle-of-attack before rotation?  (I distinctly recall reading this in some flight training material for civilian jet pilots.)  That could hugely affect the lift force, compared to, say, a Cessna 172... or an F-16... or a Super Etendard (sits very nose-high, see https://upload.wikimedia.org/wikipedia/commons/1/19/Super_Etendard_ARA_204.jpg and https://upload.wikimedia.org/wikipedia/commons/a/af/CdG-photo173.jpg , from https://en.wikipedia.org/wiki/Dassault-Breguet_Super_%C3%89tendard ).

Re -- Don't business jets often have a design that puts the wing at a slight negative angle-of-attack before rotation? -- primarily to maximize braking performance after landing.

So, arguably the question is ambiguous, unless you specify that you are interested in answers covering a broad range of aircraft designs (in which case the question might be overly broad?)

Re -- compared to, say, a Cessna 172... or an F-16... or a Super Etendard -- or a B-47 or B-52!

Ex military here, and AOA was our bread and butter during landing, but not used at all during takeoff unless it was an emergency.  So I’m not sure what you are looking for in terms of crosswind correction... controls into the wind just like any other airplane.

It would seem that while the aircraft has all wheels firmly on the ground, regardless of airspeed, the angle-of-attack can be determined by just looking at the wing and assuming that the relative wind is horizontal-- unless you want to take things like induced upwash into account (which presumably will be minimized by ground effect)-- and are typical a-o-a indicators really positioned appropriately to measure such effects?  It's an interesting topic but I'm not sure we really have a defined, answerable question here--

@MichaelHall A range for AOA would perhaps be useful. Where is it in relation to 0, and where is it in relation to max L/D during the roll.

The question seems to conflate angle-of-attack indicators with "lift force" indicators-- say the aircraft has all wheels firmly on the ground-- a fixed, mildly positive a-o-a (or even zero a-o-a, for a non-symmetrical airfoil) would equate to much more lift (and less weight on the wheels) when the airspeed is high than when it is low.

I've edited the question tile to ask about how much lift the wing produces during the ground roll, as opposed to what the AOA is.

That edit doesn’t help, and frankly this is a bizarre question coming from a corporate pilot...  You should know that at zero wind the wing produces zero lift, while at rotation speed it produces lift equal to, or slightly greater than the weight of the aircraft.  At any speed in between it produces some “appreciable” amount of lift, depending on things like angle of incidence and, (as you mentioned) ground pitch attitude due the landing gear.  Voting to close unless you can clarify the exact confusion you have.

@MichaelHall If you don't change AOA at rotation speed, you are not going to get "lift equal to or slightly greater than the weight...". Please make accurate statements instead of making judgments about bizarreness.

Apology for the bizarre remark, but I have had airplanes get airborne before I made a positive rotation, so yes, the wing is producing lift.  Still a bit unsure what confuses you though, are you looking for aircraft specific examples, or something general?  Because I can try answering, but I have made lengthy answers before just to find out it wasn’t at all what the OP wanted...

Probably not all that applicable to business jets, but if you're doing a soft/rough field takeoff, you want to get weight off the wheels as soon as possible, even though you're not entirely airborne.  So yes, the wing CAN produce appreciable amounts of lift during the takeoff roll.

Back to the basics: with credit to @jamesqf for the comment about soft/rough field takeoff ... "get weight off the wheels as soon as possible".
With a cross-wind take off, we leave weight on the wheels as much as possible, then rotate.

"Since you can't crab before becoming airborne"

Rudder and ailerons become effective as speed increases, even before lift off.  The rudder in particular helps hold track while the wheel friction prevents side slipping.  Once airborne, a bank (from the ailerons) replaces the tires!  But aileron inputs should also be there during the take off roll to help hold the upwind wing down.
Generic recreational tricycle gear procedure:

Soft field: flaps down/yoke further back (increases AOA).
Cross-wind: flaps up (lower AOA) until takeoff, ailerons into wind, rudder (generally) away as needed, "brisk" rotation.

Tricycle gear aircraft are usually designed for minimal lift before rotation, because this configuration minimizes drag, shortening the take-off run.
But even with the same plane, flap/slat configuration and trim/yoke position can have a great influence on the amount of lift created before rotation, based on a given set of conditions.
Ground effects will also be much less at lower AOA.
As "25-30 ton business jets" tend to be rather expensive, one may seek training on that specific model for more definitive detail.
Airfoil specific Lift vs AOA information is also available at airfoiltools.com.

An 'appreciable amount of lift' is subjective, but with thanks to @RobertDiGiovanni's answer above, I was able to work out some example values, shown below. (I used the link to airfoiltools.com to get CL data to approximately solve the lift equation for a B737 - exact type not specified - at various speeds during the ground roll).
At an assumed constant (until rotation) AOA of 0 degrees (and thus a CL of 0.2), lift at 80 knots will be around 2000 Kg, and aprx 6500 Kg at 147 knots (147 is the Vr for a B737-500 at MTOW - 60 Tons - per b737.org.uk)
In this case, until just before rotation and the associated large increase in AOA, lift reaches a little over 10% of the weight of the aircraft.
At an AOA of 5 degrees (CL 0.6), I find lift to be 6000 Kg at 80 and 23000 Kg at 147 knots. That is a lot more significant in relation to MTOW.
Ultimately, I am looking into how the risk of lateral runway excursion on a 'slippery' crosswind takeoff evolves over time, from brake release to rotation. I should perhaps have included this info in the original question. Good unambiguous questions are quite hard to ask.
Answers are likely to remain approximate, as I've not found airfoil specifics for "my" aircraft.
The trim setting (usually set for aprx V2 for engine-out handling reasons) can cause unwanted rotation without pilot input, and may indeed need counteracting, especially in the above circumstances.
Edit: the airfoiltools.com data does not specify the flap configuration, these results may be without flaps - which is not the way most aircraft are configured for takeoff.

It would seem the ruggedness of the nosewheel assembly would play a role, as well as mass vs side area.  The military examples (some with catapult) can be pitched up because they are shot forward very rapidly.  (An Xwind TO may also benefit from full throttle).  The aileron should be helping on at least one side with downforce (but lifting on the other).  Icy may be a lot worse.

@RobertDiGiovanni Yes, some of those nose gear assemblies look less than rugged - witness a well-known 3-engine bizjet. Would also be interesting to see what kind of downforce can be generated during the ground roll by down-elevator input. And how much the nose gear can handle.

... and I remain very curious to know what the actual AOA of that B737 is during the ground roll, if anyone has any idea.

While on the ground run of an airplane during takeoff while still on the ground, especially a tricycle gear airplane, the angle of attack indicator will not move.
This does not mean the airplanes wings are not producing lift.  Remember the lift formula.  $L = C_{L} * \rho\ * SA * V^2$
The angle of incidence connecting the wings to the fuselage is most likely positive giving a positive $C_{L}$.  However, the angle of attack indicator, which is typically mounted to the side of the fuselage is showing no lift.
We know the wings are producing lift because of the correct way to takeoff during a crosswind.  The pilot must position the ailerons such that the wing is pushed down on the upwind side to prevent the wind from picking up the wing.  We are also taught to keep flying the airplane once it lands and to positions the ailerons to keep the wings down.
A lot of jets have spoilers that will extend in the event of an aborted takeoff or during the landing rollout.  The idea is to reduce the lift produced by the wings and to push the wings down allowing the tires to grip the asphalt better.
In the jets that I fly, we are taught to push forward on the yoke before VR so that the nose doesn't artificially rise before it is time.  This is only possible if lift is being created on the wings before rotation.  It also tells us the elevator is creating a nose down force during the takeoff roll.

See https://chat.stackexchange.com/rooms/138029/a-room-to-discuss-flight-dynamics for some comments-- some of which may facilitate improvement of the answer--

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What is the fastest recorded backward flying plane?
It is a well known fact that some planes like the Antonov An-2 can fly backwards since their stall speed is lower than the speed of the winds they can stably fly into. My question is what is the fastest recorded backward flying plane and is there video of this phenomenon?
In response to the comments by @Simon et al the term backwards was vague - backwards relative to the ground would have been more accurate.

A video of an harrier jet doing it.

Is that Harrier considered as hovering or flying?

I guess flying, you can't achieve supersonic speeds while flying backwards!

OK, I'll be the pedant.  The An-2 cannot fly backwards, nor can any other conventional aircraft.  If the wind is fast enough, you might have a negative ground speed but you are still flying forwards.

Modern airplanes achieve reve4rse flight by using thrust control. Are you considering this when you want your answer, or you just want to know a plane's max reverse speed while flying into a headwind ?

I'd suggest gliders is one possible source for info - especially people using mountain wave lift for altitude flights.  Station keeping in strong high-altitude winds is fairly common in that style of flying.

@Simon Not necessarily true; let's drop some science: compare speed (magnitude) vs velocity (magnitude AND direction). Physically, you cannot have negative speed, but you can have negative velocity. So, forwards and backwards flights both result in a positive speed, but only one will have a positive velocity depending which direction is chosen as the positive direction in that frame of reference. For example, if the wind was pushing you backwards, you would still have a positive speed but a negative velocity => you would be flying backwards.

I think Simon meant "negative ground speed" to mean the same thing as velocity with respect to the wind direction.  Is further definition of common words necessary?

@V-J I'm perfectly aware of the science of flight, the difference between a scalar and a vector and the definitions of common words thank you.  A conventional aircraft can only fly if the relative airflow velocity is positive with respect to the aircraft frame of reference and it's lift generation devices.  Therefore, when flying, it's speed is always positive (as will be shown by the airspeed indicator).  It is not possible to fly backwards.

@Simon I did not mean to lecture, sorry, and your point makes sense now that you mentioned the relative airflow, I didn't think of that. I cannot figure out any way to get around the definition of flying in relation to the airflow frame of reference, so you/someone should expand that to an actual answer for the question?

@V-J And I had a big smile when I wrote it ;)  I won't post an answer since I am being cheeky, a pedant and a smart a**.  I understand what the OP means and will leave it to others to answer.  I don't have a good contribution.  Cheers.

Harrier and Yak-38 are capable of reverse flight via thrust vectoring?

You should edit your question to highlight this is backward relative to the ground and not to the airmass

EDIT: This first paragraph previously only referenced the Harrier, but I've since found evidence of the Osprey doing the same, and the F-35B has since been reported to perform the feat.
The only true answers I'm aware of are the Hawker Harrier (or Harrier derivatives thereof), the Osprey, and the F-35B. These are all VTOL aircraft which can fly backwards, and can also fly very fast forward... thus they are the "fastest" aircraft which can also fly backwards.
Previously this crown belonged to the Harrier, but since the F-35B is faster it now takes the accolade of being the "fastest recorded backward flying plane": it can fly backwards, but also fly at mach 1.6.

As to your original question, the answer is that any aircraft is capable of this feat of "moving in reverse relative to the ground", if the wind speed is higher than that aircraft's stall speed.
I'm not quite sure what your question is, as you ask what is the fastest plane which can do this: Do you mean "What is the maximum speed of any aircraft which can achieve this?" or did you mean "How high can this relative speed be"
For the former: With the maximum wind speed recorded on Earth being over 230mph, any aircraft with a stall speed of 230mph or lower (ie, almost any plane), can do it. Therefore the fastest aircraft which can achieve this is the fastest aircraft on the planet. I'm not 100% sure on the fastest aircraft, but the SR-71, for example, can fly at well over Mach 3, but is also capable of flying "backwards" if the wind speed is above around 180 knots.
In theory the SR-71 could therefore fly at Mach 3 "forwards" or around 50mph "backwards" (in the context of this question) by travelling at 180 knots into a 230mph headwind. I wouldn't recommend attempting this, however....
Or to answer the real question I think you're asking which is "How fast can an aircraft performing this feat travel relative to the ground", the answer would be "the aircraft with the slowest possible stall speed" and the relative speed would be approximately 200mph.
An aircraft which can fly at under 30 knots, flying into that 230mph headwind, would be travelling "backwards" at 200mph relative to the ground, and at 30 knots relative to the wind.
So actually with it's very low stall speed the An-2 is probably a contender, although I believe there are aircraft with lower stall speeds.
(Apologies for mixing Knots and MPH almost at random in this reply: all numbers are approximate, however, so it probably doesn't matter too much. For the purposes of this answer, I'm treating 1 kt and 1 mph as approximately equal)

In the "for what its worth department": A US Marine aircraft mechanic told me the Harrier can fly 120 knots backwards.

I think you mean the F35B, which is the STOVL variant.

Technically not correct as both the Harrier and F-35B are classified as powered lift vehicles, not airplanes.

@CarloFelicione not according to any dictionary I own. "Airplane: a powered flying vehicle with fixed wings and a weight greater than that of the air it displaces". This definition is correct for both the F-35B and Harrier.

That’s all great for Merrian Webster, but in the eyes of the Law, those vehicles are categorized as Powered Lift vehicles per 14 CFR §1.1 which defines it as “a heavier-than-air aircraft capable of vertical takeoff, vertical landing, and low speed flight that depends principally on engine-driven lift devices or engine thrust for lift during these flight regimes and on nonrotating airfoil(s) for lift during horizontal flight.”

@CarloFelicione you're assuming I'm American... the laws in my country don't define what a Powered Lift vehicle is

VTOL aircraft including the Harrier and F35B can travel rearwards while airborne, but in doing so they are relying mainly or exclusively on engine thrust rather than lift from the wing to stay airborne, and so they are not flying in the true sense.
Lighter-than-air craft can also travel backwards, but are not usually considered to be aircraft.

Lighter-than-air craft are aircraft (vehicles that can fly); they're just not airplanes.

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Why did the diverted Rome - Chicago flight dump its fuel?
Having just read this story about a plane which was diverted to Belfast following a passenger's abusive and threatening behaviour, I was wondering why the plane had to dump its fuel (as explained in the news article). It seems quite wasteful, surely the airline would prefer the crew to pacify or apprehend the passenger and carry on to its destination.

half dupe to http://aviation.stackexchange.com/q/2854/609 (about dumping fuel) and the other half is related to this: http://aviation.stackexchange.com/q/8486/609 (not a dupe though)

Full dupe I'd say! Not sure how my searching didn't find this. The answers to that question address my point perfectly. Shall I delete this?

The airline would prefer the crew to pacify the passenger, but keep in mind that the crew members are not trained security guards and have limited options for restraining an unruly passenger.

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Why are there 40 737 Max planes in flight when they have been grounded as not airworthy?
Many countries have already grounded 737 Max planes and as of Mar 13, 2019 the FAA have stated:

The FAA is ordering the temporary grounding of Boeing 737 MAX aircraft (PDF) operated by U.S. airlines or in U.S. territory. The agency made this decision as a result of the data gathering process and new evidence collected at the site and analyzed today. This evidence, together with newly refined satellite data available to FAA this morning, led to this decision.

Source FAA Statement on Boeing 737 Max
So why are there currently 40 737 Max planes in flight according to FlightAware?

Who would be liable should one of these flights crash on takeoff, potentially over a densely populated urban environment?

The flightaware data is wrong.

@Ben Really? What is wrong with it?

@Ben https://uk.flightaware.com/live/flight/TOM733 shows
Aircraft information
Aircraft Type
Boeing 737 MAX 8 (twin-jet)

I don't know enough about how it gets the data but flightradar 24 gets data directly from the aircraft ADSB transmitter and it shows none of them flying at the moment. I corroborated this when flightaware displayed a Max in Australian airspace yesterday when the aircraft has been subbed to a normal 737-800.

TOM733 is currently operated by G-FDZY which is not a Max

@Ben Ah. So after checking I see FlightRadar is showing a B738 (737-800) not a MAX. Kind of invalidates my question then. If you want to write that up as an answer I will accept it.

The FAA decision was yesterday, not today.

@reirab Thanks. Updated.

some more context: https://twitter.com/flightradar24/status/1106561968473812992

@Ben, you are right. There is a large discrepancy between FlightAware and FlightRadar24!

Most of them are probably on a ferry flight. The EASA directive allows 1 transfer with up to 3 flight legs without passengers.
Some of them are travelling between countries where they are not grounded.
When a commercial plane crashes, the airline is liable, unless it can prove that the manufacturer is at fault.

I revisited the FlightAware search for B737M today (March 15th), because I was curious how the picture has changed. Same time of the day, just 1 day later:

There is now much less B737M traffic in the US, none in EU, slightly less in Asia, and increased traffic in Africa. That would be coherent with what I answered yesterday, but I was also curious about @Ben's claim that the FlightAware data is not correct. Now this is what I found:

The search in FlightAware identified 26 flights as B38M. Cross checking with FlightRadar24 delivered:

1x 737 MAX 8
18x 737 other than MAX
1x 787-9 Dreamliner
6x not found

The only 737 MAX was - according to FlightRadar24 - AAL9663 from Miami to Phoenix.
I am not sure what exactly FlightAware is showing. My guess is that they are showing the types that are planned to execute the flight.

One of them (from Agadir) is flying into Manchester Airport. They are grounded in European airspace.

They are grounded for passenger flights. The EASA directive allows 1 transfer with up to 3 legs without passengers.

"The EASA directive allows 1 transfer with up to 3 flight legs without passengers" - to get the plane to a location where any corrective action can be taken. There is (yet) no corrective action, and when there is it will be a software upgrade which can be done just about anywhere...

@DavidPostill no. you want to do any change to your aircraft at your maintenance facilities, where your technicians are, and they are not "just about anywhere"

It's generally cheaper to ferry the plane to the techs than it is to ferry the techs to the plane

Are there any countries with airlines that operate the MAX that haven't grounded it?

@DavidPostill Have you ever parked your car in long term parking at the airport? Imagine the parking fees for a 737!

@reirab some countries in Asia, Africa, and South America. Whether there are any registered there I don't know.

In reality, all airlines have incredibly high public liability insurance (or the equivalent) which would pay out if they are at fault. I’m confident Boeing have the same sort of policy (perhaps even with the same insurance company!).


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Which military aircraft does this seem to be? [F-16 vs MiG-21]
Can someone identify the aircraft based on the components, riveting style, or other technical details visible in these crash pictures?
a) Based on publicly available details, the chief suspects are MiG21-Bis or F-16. Are there US vs Soviet construction details, materials, etc that can enable identification based on these images?
b) There is a drop-tank in the images, which is claimed to be only compatible with one of these two aircraft. I'm looking for someone familiar with the MiG-21 or F-16 to comment.
Background:
Three aircraft crashed in the Kashmir region during hostilities on 27th Feb 2019. One was an Indian MiG-21bis, whose pilot ejected and was apprehended by Pakistani locals. Another was a Mi-17 helicopter, which crashed "due to technical reasons" killing six persons onboard, within Indian territory.
No information is available about the third aircraft; Indian sources claim they hit an F-16 while Pakistani spokespersons said they did not have F-16s in the area.
These are purportedly pictures of the downed third aircraft. This could be part of an F-16, JF-17, MiG-21, SU-30MKI, or Mirage in Pakistani or Indian service.

source: Photo/ANI

source: Photo/ANI

There is also a low-resolution video available via twitter, showing the droptank recovered from the site being loaded into a truck.
Link to low-resolution video on Youtube
source: @MdShafiKhatana/Twitter
Edit:
This is a recent incident. Some sources claim the image shows a part of an F-16 engine. Is this plausible?

source: Photo/ANI
Edit 2:
Is it plausible that this number "J0269" (from the above picture) can be used to identify the aircraft as an F-16B Block 20 MLU with tail number J-269 using this link?

I’d say it’s unlikely the item in the top pic is the compressor case, as pictures of accidents I have seen, the engines have been pretty much intact, even though badly damaged. There’s lots of bolts on the flanges of a case. For it come completely off, would be very unusual, IMHO. Basically, I feel your question is impossible to answer, given a single picture and the large degree of damage, rendering identification a complete guess.

Questions about ongoing crash investigations are normally off topic, I think this might just be on topic because it’s an identify from photo question. That said, I think based on the quality of the photos and the background answers are most likely to be speculation, so I’ve flagged as opinion based.

The only five aircraft expected in the area are Mig-21, F-16, JF-17, Mirage and Su-30MKII. Out of this, based on publicly available details, the chief suspects are MiG21-Bis and F-16.
Are there US vs Soviet construction details, materials, etc? In the linked video there is a drop-tank being loaded into the truck, which is claimed to be only compatible with certain aircraft. I'm looking for someone familiar with these types of aircraft to comment.

Given that L-269 was sold to Jordan, not Pakistan, and doesn't seem to have been sold on, it wouldn't be that one. As these are Pakistani soldiers taking pictures, and Pakistan denies an F-16 was shot down, I think we can assume that the pictures would not have made it past their censors had it been an F-16.

The first part of the handwriting on the box looks more like a "B" to me than a "J".

It's a MiG21. There was another photo showing the front section area and the unmistakable nose cone of the MIG21.

@HoldenMcGroyne I don't even see a nose cone, can you be more specific?

@HoldenMcGroyne Since there were three crashed aircraft on that day, with wreckage spread over a wide area as well, this question is limited to identifying from these photographs restricted to one recovery site, if possible.


text:
Is there any reason in principle that large aircraft couldn't be converted to be controlled remotely?
Suppose the pilot or pilots of a plane become incapacitated for whatever reason. At the moment, there is nothing that can be done from the outside to stop it other than to shoot it down (am I right?).
Would it in theory be possible that planes have a 'safe landing' program built in that, at a signal from the ground takes over control? It then does everything necessary to land correctly and automatically at a nearby airport.
I realise I am making a lot of assumptions here. My main question is not about the logistics  of what would have to happen on the ground, nor is it about whether a new generation of terrorists could hack into such a system for their own purposes. It is about how easily current autopilots could be adapted to have a 'land safely' option. What modifications would the manufacturers have to install within the plane itself that would make this possible?
Summary

Is it true that currently, the only way to control a runaway aircraft is to shoot it down?
In theory could an existing autopilot have a simple interface that is retrofitted such that a single signal from the ground  sets it in 'return to base' mode and produces a safe landing?

The probability of being hijacked is very much lower than the proability of external remote control being hacked or malfunctioning.  Therefore, what problem would it solve?

If the good-guys can remote-control the airplane, the bad-guys can to.
Every system can be hacked.  By trying to block one attack vector, you've added an additional vector.

@abelenky Not only would this add another attack vector, hacking into a remote control system would likely be easier than physically hijacking a plane.

@Freeman has it right.  Imagine a simple scenario where the runway is not safe for landing: covered with snow and ice, 50kts crosswind, and maintenance vehicles on the runway.  If an attacker could issue the "normal" automatic-landing command, the landing would be worse than staying up in the air, and there'd be little the pilot could do about it.

@Simon, I am not suggesting it as a solution. I am asking if it is possible in principle. Of course it could be a solution for a smaller plane with only one pilot  who becomes unwell.

Related for conversion of fighters to drones

While it's certainly possible with light GA aircraft, it would be incredibly expensive to install all the ILS systems on your average C172.

@FreeMan Don't most 172s already have ILS receivers? Now, installing an autopilot that is capable of flying a coupled approach and is certified for Cat IIIb is another matter...

@reirab: IANAP - that was the intent of my statement

Yes for reasons of hacking prevention. There is no way to be absolutely sure any interface can't be hacked to crash the plane remotely into a suburb.
Yes autopilots can follow a track of navigation marks to an airfield and can auto-land using the ILS.

But again there is no way to ensure only signals from people who have the best intentions with the plane can activate that mode.

Very, very few aircraft are set up so that the autopilot can extend flaps & lower the langing gear. Without a cooperative pilot in the cockpit to manipulate those controls, even Autoland can't land the plane successfully.

Valid, @RalphJ, however a no-flaps, no-gear landing at an airport with emergency personnel standing ready would likely result in fewer injuries than the same plane flowing into a building. Not that I'm supporting the idea... Also: running out of fuel will cause the plane to land successfully, if not safely. ;)

The DLR ATTAS does it already since 30 years, and there is no technical reason why this should not be possible on any airliner.

@PeterKämpf  "Could be" but isn't yet. It wouldn't be all that hard to design or retrofit equipment so the autopilot could tune the ILS, extend the flaps, arm the speedbrake and autobrakes, lower the landing gear, set the MCP altitude down to GS intercept altitude, engage the approach mode, and extend the thrust reversers after touchdown. But without that, you're looking, best case, at a coupled LNAV/VNAV approach to a high-speed (no flaps) gear-up crash landing on the runway.  (Oh, with the engines still running, or burning, after the wreckage slides to a stop & pax start to evacuate.)

@RalphJ: The "couldn't be" is part of the question, so my comment refers to the possibility. You're right, in reality it isn't yet.

In principle, no. But there are problems in practice.

It is true that at present, the only way to stop a runaway aircraft is to shoot it down (unless there is some way of getting into the cockpit, like in movies).
Modern aircraft (at-least the most recent ones) are programmed (via their fly-by-wire computers) to land automatically without any human interference (except for setting flaps etc., as already noted) and these can be programmed to do a landing on command. However, whether they can be used in practice is different altogether:

The autopilot landing is instrumented and is not possible in all the airports. The computer has to 'decide' where to land based on fuel situation, among other things.
What will happen if the runway contaminated? or one of the tires blow during touchdown? If the crosswind is more than what the autopilot is designed for? There are too many variables and in most cases it will do more harm than good.
And most importantly, what if the signal is sent by by someone intending to crash the aircraft? what if some one sends the signal (even accidentally) during takeoff?

Adding auto-land on remote command is more trouble than its worth.

Actually, it doesn't even need to have fly-by-wire. It 'just' needs an autopilot that can be coupled to the ILS receiver and that is certified for Cat IIIb operations. Lots of transport category jets before the age of fly-by-wire had operational autoland systems.


text:
Low visibility spins and spirals: difficult-to-understand explanation of false perception
I'm not a pilot.
In the following excellent explanatory video I understand everything except for a single point.
The presenter says that in cloud, if the instruments tell the pilot to level the wings when the plane is tilting to the left, the pilot's reaction will be to bank even more steeply to the left, because they will believe they are in a severe right-hand bank.
Spin, Spin, Spin!  2:00  (Video)
Given that, according to the presenter, the inner ear is telling the pilot that they are currently horizontal, why would the pilot assume or feel anything about which way they should correct?  Isn't it 50/50 whether they choose to roll in the right sense or the wrong sense?

Spatial disorientation is hard to describe even when you've experienced it first hand. I'm looking forward to someone doing so here, because I'm struggling to.

@Jamiec How did I do?

@StephenS amazing. I learned a lot about the cause.

Do you ever notice how weird it is that you can have a cup of coffee sitting flat and level on your meal tray in an aircraft when the plane is banked 30-deg into a turn?  If you couldn't look out the window, would you believe the plane was halfway sideways?

@J... -- yes, because I weigh more!

Your vestibular system can only recognize acceleration. Your brain combines that with visual inputs to produce spatial orientation. (If the two disagree, you may get motion sickness.)
When you are in a sustained left bank, your vestibular system stabilizes and feels no acceleration. Without a usable visual input, your brain will convince itself that you are instead straight and level. This is spatial disorientation.
If you then look at the instruments and try to correct yourself to actual straight and level flight, the vestibular system feels that change in acceleration as starting a climbing right bank, which now feels wrong. It orders you to bank back to the left even harder to make itself feel “normal” again.
It’s not a 50/50 chance; once disorientation sets in, your body will consistently tell you to do exactly the opposite of what you should do. That’s why it’s so deadly.

This is probably correct, but explained in a weird way. There is certainly acceleration present in any turn, coordinated or not. Without acceleration we fly on a line.

@VladimirF I think he's talking about angular acceleration for the most part.  That makes up accelerating in three of the six degrees of freedom we usually consider for motion: pitch, roll, and yaw.  We can also sense linear acceleration in the other three degrees of freedom: thrust (forwards), slip (sideways), and heave (upwards), but roll is the most important in this context.

You have a good hunch but a bit of the detail is lacking. The vestibular system has three linear accelerometers and three angular velocity sensors. So it can recognize both linear acceleration and angular rotation. In fact, the angular velocity sensors are oriented in plane of the ocular muscles, so that the ocular muscles can stabilize the image on our retina with a minimum of neural network latency - IIRC there's a single synapse or two between the semicircular canals and the ocular muscles.

To enlarge slightly upon StephenS's answer, if the banked turn is properly coordinated, then the pilot feels only the G-force of the turn and no shear force in his or her seat, and concludes that (s)he is not turning left but climbing.
The hapless pilot then notices that (because the plane is in a banked turn) it is showing a descent on the VSI gauge. Pilot then tries to climb by pulling back on the yoke, which for a steep turn tightens the turn and increases the G-force, making the pilot feel the plane is climbing more steeply.
By that point the altimeter has begun to unwind while at the same time the pilot feels as if the plane were still climbing. If (s)he happens to look at the attitude gyro, (s)he will then see the plane is in a very steep left bank and in a nose-down attitude even though the G-force makes it feel like the plane is climbing.
Cognitive dissonance sets in and the pilot panics and reefs back still harder on the yoke.  Now the plane is in a high-speed spiral dive and if the cloud bank extends all the way to the ground, the plane flies into the ground in a hard bank, nose-down, with the VSI pegged at -3000 ft/min or thereabouts.

Would an alert pilot be able to use a magnetic compass to determine what's going on and, if e.g. the magnetic compass is turning clockwise, turn the yoke left until the compass stabilizes?

@supercat a properly trained pilot could do that with several of the instruments, but probably not the mag compass, it has several turning errors that make it pretty difficult to interpret in any regime other than straight and level flight.

@nexus_2006: Would a simple magnetic compass not show the plane's heading as turning clockwise if it is banked to the right and consequently yawing in that direction?  I understand that the exact heading shown may not be meaningful if the plane is banked, but if a plane is anywhere close to horizontal I would expect yaw would show up on the compass.  Why wouldn't it?

@supercat no a simple compass doesn't show that.  For example, if you don't change your heading at all, but change your speed, the compass will show a turn, then swing left and right before it settles back to the original heading.  If you're facing (it's been a while so I might have it precisely backwards) south and start a turn, the compass will show a turn the other way.  These errors aren't hard to memorize, but they're very hard to remember and account for in the heat of the moment.  The tool you're looking for is the DG/HSI - a gyro-stabilized compass card.

@nexus_2006: I wonder if a simple electronic yaw-speed indicator would be useful.  Electronic gyros are very cheap if one is willing to tolerate some speed uncertainty or positional drift.  Making a stable electronic artificial horizon may be expensive, but I would think that a measurement of yaw speed could be useful even if it had a few degrees per minute of uncertainty.

@supercat yaw speed indicators exist and are commonly available in aircraft as "turn coordinators."

This is a much better explanation.

Do instrument panels not have a gyroscope like this? https://imgur.com/tp3Xj4z
That would make spatial orientation a breeze.

@AnnoyinC IFR rated planes absolutely have. But the point is you must ignore your senses and only trust the attitude indicator. If you get into a cloud with a simple VFR-only plane, it is extremely dangerous. Even in a well equipped plane and a non-rated pilot it is dangerous.

@supercat yes those have been common installs in GA aircraft for many decades, and ifr pilots train to fly the plane solely referencing the yaw indicating gyro, in case the artificial horizon fails, it's referred to as partial panel training.

@nexus_2006: I would think a simple yaw-indicator gyro should be cheap enough that there'd be no reason for even a VFR pilot not to have one.  A full-fledged artificial horizon is expensive, and there are many ways they can go wrong, but a simple yaw-indicator gyro could be built with less than $10 worth of parts or implemented as an application on almost any phone (though I'd probably be more confident in a stand-alone unit).  How much training would be required to teach a pilot to hold a somewhat steady attitude in zero-visibility conditions even given just a yaw indicator and altimeter?

@supercat As an IR student...a LOT more than you might think.  The inner ear is extremely powerful in its insistence that the integrated worldview generated from it is correct at all times.  The only thing more powerful by nature is the horizon lock generated from the Mk1 eyeball, which acts to nearly immediately reset the integrators used to process the inner ear acceleration inputs (this is why if said VFR pilot pops out sometimes they regain control).  A significant amount of IR training (and IR currency) is acclimating to using the instruments vs. natural senses at all times.

@madscientist159: If a pilot who had lost visibility while in straight and level flight were to focus on keeping the yaw rate centered around zero and the altimeter stationary, how substantial would deceptive g forces be?  Once a plane starts to spiral, it may be hard to tune out such forces, but I would think that the plane is anywhere near straight and level flight, a focus on the two aforementioned instruments would allow one to keep it that way with minimal deceptive g forces.

@supercat "Gyro drift" of the inner ear will start to occur immediately even under those conditions.  As to how long it would take to become a problem (i.e. the pilot starts to feel like they're banking even though they're in straight+level light), it depends on a number of factors.  Without the ability to focus on the instruments and override sensations the pilot has anywhere from seconds to minutes -- for example, on entry to the cloud was there a false horizon generated?  That'll make things a lot worse.  Is the pilot moving their head around a lot?  Again, much worse.

@madscientist159: Of course one needs to focus on the instruments, but I would think that one could fairly easily practice by setting up a "keep the readouts centered" handheld game that one could play inside a moving car which is traveling around winding roads.  Tuning out acceleration would be a skill one one would need to practice, but such training wouldn't seem complicated.

@supercat I'm typing up an answer to the original question -- it's not tuning out the transient acceleration that's the problem, it's tuning out the internal state vectors that scream you're in a 45 degree bank and diving at the ground when you're actually straight and level.

@madscientist159: Why would the internal state vectors get more out of whack when sitting in an airplane that's flying straight and level and staring at instruments than when  sitting at an office desk staring at a computer display?

@supercat The only condition where those would be comparable is in absolutely glassy smooth air with no preceding false horizon type inputs (i.e. uniform lighting top to bottom out the window, etc.).  In that case sure, SD is unlikely to occur if straight and level flight is maintained.  In reality cloudy air is rarely so nice -- the acceleration inputs from turbulence etc. cause rapid integrator drift and wham you have a nice case of SD.

@supercat you're right, a simple gyro-based yaw indicator is cheap and simple, as I mentioned, nearly every GA aircraft built for decades has had one.  I have a friend with a 1960s VFR-only Skyline, which came with an OEM yaw gyro as standard equipment, that's how long it's been standard.

To elaborate even a bit further on the existing answers, there are a couple of items that should be kept in mind.
First, the entire human spatial orientation system works as a sort of sensor fusion between fast (but prone to drift) sensor inputs and slow (but accurate) sensor inputs.  Fast / drift-prone inputs come from acceleration sensors -- the inner ear (rotation), the "seat of the pants" feeling (G-force, linear acceleration).  Slow but accurate inputs come from the eyes (horizon lock) and proprioception (when standing upright, pressure sensed in feet + autonomous balance inputs required to stay upright).  To make matters worse, our inner ear is designed only to function in two dimensions, and lacks certain features of avian inner ears that would help reduce the drift in three dimensions.
If this sounds similar to the systems spacecraft use, it's because it is.  They have gyros and star trackers, and like our own senses the gyros drift while the star trackers are too slow to maintain orientation under motion.
Fundamentally, the problem here is that the brain is performing a double integration automatically, every waking second of every day, using the visual system to keep drift in check.  It is very, VERY hard to discard the bad state vectors generated from the system without being able to see a horizon.  Without visual references, as the integrated values from the inner ears drift more and more away from reality, expected position (i.e. predicted path of travel and even current location) will start to drift as well.
An untrained brain (or even one sufficiently far out of IR currency) will use the synthetic state vectors (predicted path of travel, integrated attitude) generated by this autonomous system, even in many cases overriding the gyro in front of it ("it's broken", etc.).  If you try to override, that same internal autonomous system will continue to drift and will scream even louder and louder at you that you're making the problem worse with your inputs.
To make matters even worse, many other higher level functions within the human body rely on those internal state vectors being accurate.  When you're running for example and start turning, you'll notice your eyes start to lead out the turn (looking in the direction of the turn) and there are subtle posture shifts that occur in anticipation of the turn.  If those vectors are wrong, you can actually end up looking slightly away from the object you want to see, or unconsciously start putting in a bit of compensatory yoke pressure.
This integrated positioning system is so deep within the brain and so fundamental to daily life (without it, jumping, running, or even walking would be out of the question) that when an IR pilot gets "the leans" it can take every ounce of effort and focus to just override that system.  A pilot not familiar with that experience is likely to panic and unconsciously ignore the instruments, even if they were able to interpret what the instruments were saying under normal conditions.

TL;DR: Beware the double whammy: spins caused by spatial disorientation can cause inappropriate vestibular nystagmus that then causes loss of visual acuity making you unable to read small features on instruments potentially depriving you of critical instrument feedback needed to reacquire spatial awareness.
In addition to the other answers, the yet other confounding (and deadly) factor is vestibular nystagmus. Nystagmus is the sawtooth (pendular) motion of the eyes, and is normally a desirable oculomotor function, used to both reacquire the image on the retina (the fast slope of the sawtooth), and to stabilize the image on the retina (the slow slope of the sawtooth). Unfortunately, the vestibular inputs experienced in flight, and especially during aerobatics, spins, or other high-g maneuvers, are not mostly inappropriate for stabilizing the image on the retina. Such vestibular input may cause inappropriate and undesirable nystagmus. Suppression of this nystagmus can be learned under feedback (e.g. biofeedback from an eye tracker), and is also naturally present to an extent. Some substances, like alcohol, decrease the effectiveness of the suppression, and lower the threshold for vestibular nystagmus to occur. Individual threshold and sensitivity to various substances in that respect seems to be highly variable and is influenced by genetic and environmental factors.
Inappropriate nystagmus is bad news, because it decreases the visual acuity - i.e. decreases the maximum spatial frequencies we can visually resolve, while, paradoxically, increasing the apparent contrast of low spatial frequency features. Under nystagmus, we lose the ability to see small details, while the scene overall seems to have higher contrast. This causes a dangerous sensation of "seeing better" while the opposite is happening.
If the instruments have sufficiently low contrast and/or small features, e.g. the thin vectors that the glass cockpits and HUDs love for some inexplicable reason, the retina won't be able to resolve them. Alas, our visual system is used to filling in the blanks with expected information, and will gladly substitute whatever we'd deem "expected" based on prior experience and our idea of spatial orientation - based in part on the inappropriate vestibular inputs. This, unfortunately, is a good recipe for controlled flight into terrain, and is a real problem for e.g. military fighter pilots.

Spatial disorientation, spins, and illusions are complex subjects each.  In this case, the initial explanation in the video is straightforward.  If one gets into a particular flight attitude, especially slowly, and doesn't feel one's self getting there (slowly creeping into a bank), the body doesn't know it's in that attitude (eg, bank).  The body thinks nothing has occurred to move it from level flight.  The sensory perception in the inner ear hasn't indicated a change from level to the bank, so when one sees the instrument indicating a bank, the natural inclination is to believe the one instrument that's always been true...the brain and the body.
Of course, this isn't true.  The instrument is correct.  But one perceives the instrument to be incorrect; after all, how did one get into that bank, without sensing it.  If one suddenly rights the airplane according to the instrument, or in other words returns the airplane to level flight, now the body senses a movement.  This movement is contrary to what the body believes; the body believes it was level, but the movement now is sensed as a bank.
When the body senses a bank, but the instrument is showing level, this is confirmation bias: the body believed it was correct before (even though it wasn't), and thus that the instrument was incorrect.  Now, having moved the airplane back to level flight, the body is receiving a signal of movement, and believes itself now banked...the instrument says it's not in a bank.  This confirms the previous believe, or is confirmation bias, implying that the body was correct all along, and the instrument wrong.  This furthers distrust of the instrument.
What has really occurred is that the pilot has returned the airplane to level flight, but perceives himself or herself to have entered a bank.  Now a sensory conflict exists.  Which is correct?  Instrument training will tell the pilot to believe his instruments.  A lifetime of standing upright will tell the pilot to believe his inner ear.  If the pilot does not follow the instrument indications, he can roll back into the bank where he was, and even steepen it; each upset or correction can make the sensation worse.
In the process, the upset is further worsened if there are changes in pitch, or in speed.  Changes in speed will usually be perceived as changes in pitch.  As bank angle increases, these changes are further complicated by increasing G load, or unload, which may be perceived as pitching moments, further complicating the matter, and a pilot in a bank who begins to apply pitch can further complicate the matter, steepening the bank, unloading the wing, increasing or decreasing senses of bank, speed, and pitch.
The immediate solution is simple in description, harder when experiencing strong conflicting sensations (disorientation).  Fly the instruments.  Easier said than done, especially initially when one wants to believe one's own senses.  I have seen very experienced pilots, on several occasions, become disoriented even in visual conditions, or visual conditions with illusions.  In one case, in a 747, I took the controls briefly when the pilot became disoriented with a sloping horizon illusion.  We were at night, departing Bahrain, and a combination of dark, fires on oil rigs in the gulf, and stars in the sky combined to disorient the pilot.  It only took a moment for him to regain his bearings, but it does happen.  I saw the same thing once flying into Liege in the daytime in reduced visibility, but still visual conditions, when turning final.  I have experienced the same thing myself, both as a student and as a seasoned professional, and it's very real.  The solution: fly the instruments, but again, easier said in some cases, than done, and it doesn't change the strong, sometimes seemingly overpowering sensation that what the body feels is correct, and what the instruments are telling you, is not.
This is the reason we don't just look at one instrument, but crosscheck them, and interpret them: to ensure that what we're seeing is correct, and that we're seeing the whole picture.
In a spin, the effects are magnified significantly, with numerous factors coming into play.  To complicate that, spins are not stead-state events, staying the same; they change dynamically due to a number of factors, and physical and psychological factors combine to cause very powerful illusions that can lead one to make incorrect choices and further aggravate the situation, rather than effect a recovery.

This finally clicked. I'm sure reading all the answers contributed but, reading this, the penny dropped. As land-dwellers, we don't bank!, or at least not for long. We tend to remain laterally upright and gravity always comes from the same direction. When flying, "gravity" comes partly from the Earth and partly from inward acceleration.  If I have understood then, provided you can ignore your inner ear long enough to fly straight and level for a few seconds - by the instruments, everything will fit back together again. Am I right? So in low visibility use instruments constantly.

I don't know that a few seconds is the fix, but understanding the instruments and using them to maintain orientation is the correct choice.  It's equally important to cross check them, so that one does not follow an incorrect instrument (a bad attitude gyro, for example).    If you've ever attempted to stand after laying down or sleeping, and found yourself struggling for balance, you get the concept.  A stable reference is needed.  Most of us would grab something and hang on, or sit back down, or let someone steady us.  In flight, we do that by focusing on instrument indications.

authors: Vladimir F Героям слава


text:
Why are cockpit alarms still so distracting and unable to be silenced?
I'm watching video RV 10 N783V My 1st Emergency
At 8:45 a stall alarm goes off and is a horrible piercing whistle. Why? Surely the pilot has enough distractions without also being deafened while trying to talk to ATC.
Isn't there a better way of indicating a continuing alert, and why can't pilots switch the the thing off when they need to?

EDIT: The video shows that it is a false-positive warning. The pilot eventually manages to switch it off by resetting all his electronics.

@ymb1 While I think it may be relevant if the OP were asking about this specific situation, it seems the OP is more interested in why they can't be turned off.

I never liked the gear horn in the CRJs (Rockwell Collins GPWS). It sounds exactly like the old steady dual frequency tone you got on TV stations when they went off the air overnight.  I found that particular sound very easy to blend into background when under some high stress situation in the sim.  The saving grace was you'd get "Too Low - Gear" if you ignored the warning horn because you were saturated with crises and got too close the ground.

"...while trying to talk to ATC". In a situation with a stall warning, talking to ATC should be the LAST priority. Aviate - Navigate - Communicate. A stall warning should absolutely override the radio.

@quietflyer How can you be sure it's a false alert? AF447 comes to mind

For those that didn't watch the video, the stall warning was caused by an iced-over pitot tube, supposedly.  The pilot realized he wasn't stalling before he realized the icing condition.  Not sure how the stall warning actually works on this aircraft - the pilot also mentioned the aoa indicator not working.  Would that have separate icing protection?  Or is it somehow driven from the pitot tube, by factoring in the g-loading?

Because the opposite problem can be far worse

ATC hearing the stall alarm surely can react in dealing the situation with respect to surrounding traffic.

If you can't focus through a stall alarm then perhaps...

Alarm: "Stall Warning!  Stall Warning!!".  Pilot: hits snooze.

A stall condition needs to be handled now, and once it's handled, the alarm will go away. What you don't want to happen is you are in an approaching stall condition, the pilot hits a "silence" button while the situation gets worse without the plane telling them.
An emergency is "AVIATE, NAVIGATE, COMMUNICATE" in that order. Fly the plane first, point it where you want to go second, and third, only if you have time/resources, is to talk to ATC about it. The pilot should be fixing the problem first, focus on flying the plane, ATC can wait.
They can't be turned off for that reason. Deal with the problem and the alarm goes away, you don't want to silence the alarm and forget about it. There is some merit to "overloading", where multiple alarms are happening at the same time, or when the pilot focuses on a low priority item and forgets to fly the airplane (Eastern Air 401).

"AVIATE, NAVIGATE, COMMUNICATE" -  All the time, not just in emergencies.

"Deal with the problem and the alarm goes away" was unfortunately part of the accident chain for AF447, as in that accident, the alarm went away while the problem was being made worse, due to very low airspeed, while it started sounding again when the crew dealt with the problem and the airspeed began to increase. But that goes to show how ingrained "deal with the problem and the alarm goes away" is, to the point the crew continued to exacerbate the situation, perhaps because making the problem worse did happen to silence the alarm.

@ZachLipton I would trust the airplane tech way longer than any human - and so did the pilots. It was the wrong call in this situation, but how many accidents would happen, if there were no tech and only humans to fly the plane?

@ZachLipton the issue is dealing correctly with the problem, not a general rant on doing things just to turn off alarms :)


text:
Aircraft progress: Evolution or design?
This video of a Curtiss Pusher is stunning. Had I been around when it was new, I would have stopped there!

Question: What processes led to the aircraft of today?

Trial and error (evolution)
Better understanding of aerodynamics (design)

The easy answer is "Both!" but I imagine the emphasis changed over time. We started with the idea of ornithopters (da Vinci) and continued with wood canvas and string. At what point did science truly take over from empiricism? Was it with the advent of fast computing power?
Of course, such are the advancements of knowledge that a pedal-powered ornithopter has been made although it looks very different from Leonardo's.

I think you can improve the question by applying stricter definitions of the terms evolution, design, science and empiricism. If I read between the lines, I get the feeling you are interested in how the roles of empiricism and rationalism in the evolution of aircraft design have changed over time. Note that both empiricism and rationalism have a role in science and in evolution of design. As it stands, your question contrasts empiricism with science, and evolution with design, but they are not opposite terms.

Paragraph 3: "Your questions should be reasonably scoped. If you can imagine an entire book that answers your question, you’re asking too much."

The main driving forces behind airplane progress have been 1) better materials to make them out of and 2) better engines to power them with.
Better materials mean greater strength and safety. Better engines mean more power and greater reliability.
Greater strength and more power mean more payload, speed, and range. More safety and reliability mean reduced costs and broader acceptance of the technology.

Of course, the main driving force behind better engines is better materials to make them out of :)

@sanchises, as a recovering ex-materials scientist, I agree 100%. Better lubricants too.


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What happens to a large plane after a successful gear-up landing?
There are plenty of videos of non-fatal gear-up landings - even of airliners. I can find none that show the recovery of the aircraft after safe evacuation of crew and passengers and completion of safety procedures.

How is the runway cleared? Is the plane towed away (scraping along the ground)? Are there cranes available in large airports? Can a single crane lift and move a large airliner?
Is the plane considered a write-off or can some be repaired and continue in service? Where would such repairs take place?

This answer varies wildly depending on the size and type of aircraft involved, but in general:
How is the runway cleared?
They remove the aircraft, then sweep the runway for smaller debris and then inspect the tarmac to make sure the aircraft didn't gouge into it, and tear up chunks.
Is the plane towed away (scraping along the ground)?
No. The aircraft will usually be lifted and placed onto an oversized platform with either cranes or hydraulic  Jacks, and then towed. Dragging it along the tarmac would damage the tarmac (more so then the landing already did) and do further damage to the aircraft.
Are there cranes available in large airports?
Gear up landings (and catastrophic hard landings where the gear collapses) are so rare that no airport (that I'm aware of) has the heavy duty mobile cranes required standing by. It would cost way too much to maintain them and keep operators for them on the payroll when they'd just sit and rust for years and MAYBE be useful for 3 or 4 days. It is much cheaper to hire a crane and operator.
Can a single crane lift and move a large airliner?
Maybe; aircraft manufacturers will often publish manuals for how to recover and salvage the aircraft, and the crew removing the aircraft would refer to those.
Is the plane considered a write-off or can some be repaired and continue in service?
Not necessarily. This part varies depending on the age of the aircraft, how hard the landing was, and a million other factors, but the aircraft can usually be salvaged. The repairs could be astronomically expensive, and the work could take several months if not a year or more.
Where would such repairs take place?
This also depends. If the airline has a hanger at the airport where the plane is being salvaged from, the answer is simple. If not, that's when it gets tricky and expensive. Usually this means renting hangar space (which is SO much more expensive then any other commercial space) and either flying in your own mechanics or hiring a local crew. The necessary repairs and inspections would be done to get it to the point where it could safely fly back to an airport where the airline has the personnel and equipment to finish repairs.


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Could propeller wash provide sufficient lift to take off - even in theory?
I know this seems a crazy thing to ask but it is not the same as lifting oneself by the bootstraps. If you try to lift yourself that way, there are two equal and opposite forces, yet there are experiments with muscle powered planes that work.
So, provided the plane was stabilised somehow, and the wings were designed for the purpose, could propellor wash theoretically lift the plane? If not why not?

Note
I understand that a normal plane would start to move forward. Please assume that the plane is restrained from the rear by a cable and that the experiment takes place in the absence of wind.

It certainly could, think of a wind tunnel. However I guess the propeller would have to have the same span as the wings. so it's not very practical.

Related

That’s the whole idea behind Channel Wings.

gyros fly more or less this way.

muscle powered planes - don't need experiments; birds have been proving it works for longer than humans have existed

Yes.  The wing doesn't care what is causing air to flow past it.  Headwind, propwash, 747 wake, gopher sneezes.
If the airplane is restrained from forward motion, and the propwash over most of the wing is fast enough, let's say more than the airplane's stall speed, then the wing must generate enough lift to support the airplane, causing it to take off.
It's not so much a matter of designing the wing specially, as making the airplane tolerate the many large props needed, and the weight of the engines.  That much power is too much for efficient cruise.  But it's easy to implement with a one pound model airplane.

(+1) The AoA must also be factored in: airflow faster than stall speed isn't sufficient to ensure liftoff.

Follow-on question: how many gophers sneezing in sync would be required to make a 747 lift off?

But it's easy to implement with a one pound model airplane  Well, a 0.0000001lb airplane could just drift on the air as a perfect sphere with no airfoils at all.  I don't think leveraging the scaling laws of the universe is a valid approach. Scale models of aircraft don't behave at all the same as full size ones. While in theory we may be able to construct a plane that lifts under its own propwash, I feel it may be the type of situation that is so inefficient that we push up against fundamental limits of the materials we have to construct the vehicle with, making it realistically impossible.

Human sneezes clock in at about 4.5 m/s.  This article reports that ordinary breathing could power about a microwatt. Unfortunately I have no idea how to convert that into the number of human sneezes necessary, let alone gopher sneezes. Maybe this should be a new question.

It would take about 120 sparrow farts to equal one gopher sneeze.

So human breathing, about 4 sec/breath, is a microwatt?  Sustained sneezing is about as fast. Gophers breathe 3x faster, but their lungs are 300x smaller.  So one steadily sneezing gopher yields 10 nanowatts.  A 747 launch needs 90 megawatts, or 900 quadrillion sneezing gophers, covering a square about a thousand miles on a side.

@CamilleGoudeseune Man...  Not even a mole of gophers.

@Eric, thank goodness.  https://what-if.xkcd.com/4/

European or African gophers?

@SebastianLenartowicz That seems like an ideal candidate to ask Randell Munroe! I mean, who else has time to spend the day or two one would need to come up with a robust answer? Who else would know (or be able to find) the one zoologist who actually wrote a paper about gopher sneezes?? (Ans if we continue to talk about it we poison all google searches!)

@RossPresser Read carefully: The jolly researchers in the article say that they can harvest a microwatt from vibrations caused by breathing. The overall power of the air movement is probably orders of magnitude larger, especially if you huff and puff to lift this B747 ;-).

@CamilleGoudeseune This is the best laugh I have had all year. Thank you!

Recalculation.  To measure efficient energy transfer from breath, use a party balloon, which NIST says stores 255 lbf-ft, or 350 J.  A human inflates one in 20 seconds, so 18 W.  A gopher is 100x less, 0.18 W.  90 MW / 0.18 W yields 500M gophers at least, covering Wittman Field (OSH) plus Camp Scholler.

In principle yes, but why would you do it? For vertical take-off this would be grossly inefficient.
Lift is produced by deflecting air downwards.
This becomes easier as more air is available for deflection since the amount of deflection needed for a given lift can be reduced. However, when all air movement is provided by the propeller, why reduce efficiency by blowing it horizontally over a wing, where it creates friction? Wouldn't it be better to direct this airflow directly downwards so no further deflection is needed?
Any deflection will incur losses, so taking the detour over the wing complicates things needlessly. That does not mean this hasn't been tried –as qq jkztd points out in the comments, the Ryan VZ-3 used this concept, albeit with poor results.

Ryan 92 VZ-3, rebuilt after the crash (picture source).
For a theoretical approach the propeller diameter would need to be as large as the half span of the aircraft, with both propellers mounted at mid span. Now the landing gear also needs to be longer than quarter span in order to let them spin freely. Next, the wing needs flaps which are able to deflect the flow of air by 90° which will involve some active blowing. This becomes quite complex quickly, so a design like the one below looks more promising:

Vertol Model 76 VZ-2 (picture source) was the first tilt wing design which successfully transitioned between vertical and horizontal flight and was built for the same purpose as the VZ-3. While not any more visually appealing than the VZ-3, it had a longer career: It flew first (in 1957 as opposed to 1959 for the VZ-3) and was used until 1965 while the VZ-3 was retired in 1961.

Interestingly - thrust per power increases with rotor area - whether a single rotor or N smaller rotors. Hence the large rotor area on anything that wants to utilise raw rotor lift.

@qqjkztd: Thank you for the information! Admittedly, the VZ-2 was a more practical design and better at vertical take-offs. The VZ-3 would always create some forward thrust so a purely vertical take-off would be impossible.

Restricting the question to approximately horizontal airflow ... it's been tried.
The Custer Channel Wing was one that tried ... it didn't quite make it, but was claimed to be able to fly at 8 to 11 mph. That may have been optimistic but the CCW5 (pictured : image from linked Wiki) apparently flew as slow as 35mph.

And it keeps being tried... this time in conjunction with the Coanda Effect ... results not reported so far.

WOW - what a great answer, best here

Presumably you are referring to using wings fixed to the airframe with props driving air over them.
If instead you move the wing through the air to create airflow over it you "cut out the middleman" and end up with a helicopter or typical multirotor craft.
Similarly an ornithopter moves the wing through the air to attain lift.

Downvotes expected. That's life. Still seemed useful to add.

Absolutely. Here's what it looks like:

It's a turbojet here (this is an F-35 engine) but from a physics standpoint there's no reason you couldn't do it with a propeller.
So long as you have some means of directing a sufficient portion of the thrust downward, you can lift off. An airfoil would also redirect the thrust slightly downward, but far less efficiently than a nozzle.
This wouldn't be even remotely practical with a normal engine and airfoil. The physics works though, if your engine can produce enough thrust to get the required downward component.

@fectin I understand the difference, and I think you missed the point. Lift is a form of thrust in the sense that both are forces. The question proposes a scenario where an airfoil converts horizontal-ish engine thrust into lifting thrust. The pictured design is a much more efficient way to do that. But the physics, from a standpoint of arrangement of forces, is exactly the same.

@fectin Thanks, those are great examples - that's actually almost precisely the point I was hoping to make for the OP: thinking about it in that way makes it easy to come up with scenarios one can use to prove to themselves that it's possible.

My mistake: that last comment does help! I understand your point better now, but it didn't come through in your answer.

While a turbofan not a turbojet, the F35 is actually not an example (or at least little more than a helicopter is), as it incorporates a vertical-axis shaft driven lift fan front of the engine, in addition to vectoring the flow out the back.   The example you probably want is the Kestrel/Harrier system which is a (multiply) thrust vectored turbofan.


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How are timed flybys executed, and what are their accuracy?
Thought experiment: Suppose I am equipped with an ideal automobile which can reach speeds of 700mph.  On a highway, I can deftly maneuver around light traffic to achieve an average speed of 500mph.  A friend, standing on an overpass, dares me to pass under him at high speed at a precise moment in time some distance in the future giving me enough time to reach my destination (if perhaps a bit early or late).
I would find this maddenly difficult.  Likewise, aren't timed flybys difficult?  How are they executed?  Given an F16 with an average pilot, how accurate could a stadium flyby be timed?  What technology is used?
Edit:  Let be more specific.  I.  What are the exact procedures used by a flight team performing a timed stadium flyby.  II.  Given a highly trained team, what is the expected deviation from desired flyover team and actual flyover time?
I still don't think this question has been answered in detail.  Also, there must be some technique that dates from the pre-GPS era.  Even with GPS, I suspect (but I may be wrong) that the answer is more than staring at a GPS and intuiting the appropriate adjustment in speed.

See for example https://youtu.be/_dTmrSI0bts?t=19.  Presumably there is an agreement that the planes should reach the stadium just as the national anthem is ending.

Driving an aircraft can be extremely accurate.  You can fly legs of precisely known length at precise speed with the only variable being wind.  With an up to date forecast and a small amount of time to allow for errors, it is easy to arrive on time.  The Red Arrows will arrive a little early, do a circuit or two a few miles away with an exact time to run into the show and therefore, be able to arrive to the second.

All you need is something that gives you precise distance to waypoint and preferably calculated time to waypoint using your current speed. Even a basic GPS module can do that.

The way they coordinate them is actually extremely simple.  The show at a ball game (or any major event) is usually very heavily choreographed, so they know exactly when it's going to end (seriously, often down to the exact second.  They practice the heck out of those things.)  So, step number one, the organizers tell the Military the exact time for the flyover in the show.
For the militaries part, well, it's important to remember that military aviation involves a lot of instances where you have to be over a target, dropping a munition, at an extremely precise time (again, down to the second).  Otherwise you may screw up the timing of the whole operation, or the target may be gone, or the defenses may be up (etc etc).  It's really important to be precise in the military.
The procedure itself is still fairly conventional though.  You figure out what time you need to be there, then you figure out how much time it will take you to get there.  Subtract the latter from the former and boom, you have the time you need to take off.  Then all they need is a few check points to make sure they are on schedule, approaching at the proper speed.  And they adjust as needs be.
Basically, keep an eye on the clock, slow down if you're ahead of schedule, speed up if you're behind.  To increase accuracy, you may build in a holding spot near the event, that way if you're 20 minutes early (of if the planning goes out the window for the show and they're late...), you can hold there and pick the approach up again when the time is right.  It's still all about watching the speed and the clock though.  With a lot of practice, you end up hitting your waypoints, hold points and destination, with (literal) military precision.
If you want to know more details though, check out this article from ESPN: How Flyovers Hit Their Exact Marks at Games.
As a final thought, I think you may need to adjust your thought experiment.  Military aircraft can get clearance through just about any airspace prior to the actual mission.  Plus, they can approach from any direction, so it's pretty easy to find a lane that has no traffic.  So in your car thought experiment, there should have been no traffic and a straight shot to the overpass.
Plus, there should have been regular beacons (like GPS or NDB fixes) to tell you how far you are from that overpass.  And the person driving the car would have known exactly what time they needed to pass each beacon in order to get to the overpass in time.  Then, with a heck of a lot of practice, I'm sure that driver could go under that underpass at the exact right moment pretty much every single time...

"military aviation involves a lot of instances where you have to be over a target, dropping a munition, at an extremely precise time (again, down to the second)" Is that really true? Wouldn't that require predicting the enemy's actions to the nearest second, too?

@DavidRicherby I may have gotten a little overly excited with the word "extreme", but the article backs me up on the idea that military pilots are trained to be precise enough to be within a second or two at least.  I think you may have to pester RhinoDriver if you want real world examples of why that would be the case.

A friend of mine did ATC for Camp Atterbury in Indiana. He used to coordinate the fly-by for the Indianapolis 500. I believe the fly-by would be timed for the end of the National Anthem (though, this being Indiana, it might have been at the end of Back Home Again in Indiana).
They, of course, had an official schedule and knew when the song should finish. However, variations were always possible, and were expected. He was stationed at the track listening to the song, and had a radio to communicate with the pilots of whatever was flying by. They would know when they should be on target, but he would give them a more accurate count-down to ensure they arrived as close to the end of the song as possible.


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Where do airplane variant numbers come from?
For example, the new B787-8 and B787-9.  Is there any significance in why they started with -8, versus the older 737s which started from -100?  Or B757-200/300?

They come from marketing. Incidentally, there was a 787-3 being offered for a while. It was cancelled before any were built. Also, it's actually 787-8, -9, and -10, not -800, -900, and -1000. Same for the 747-8.

you're right.  I'll correct it.

Chinese superstition. The same reason Airbus went with the 380 number when 350 would have been next in line.
The Chinese sign for 8 looks like an up arrow (八) and 8 is the lucky number in Chinese. Similarly, 4 (四) is considered unlucky because the word for it (sì) sounds similar to the Mandarin word for death (sĭ).
Boeing and Airbus management court their prospective Chinese customers wherever they can because they expect their biggest sales in the next decade from that part of the world.
Originally, Boeing used three-digit numbers for their subtypes, and the last two digits represented the airline. Pan Am's number was 21, for example, so a Boeing 707-100 made to Pan Am specs was a 707-121.

Ah thank you.  I know of the chinese superstitions (i speak mandarin as well), but never though that was one of the main reasons.

[citation needed] for the claim that the 8's in recent model numbers are because it's considered lucky in China.

@DavidRicherby: You could be a Wikipedia editor. I got it from sources inside, but not in a way that could be documented here. But it is not a secret - why don't you ask Airbus directly if in doubt?

@PeterKämpf "Somebody who works for Airbus told me that..." would be fine.

The numbers are indeed chosen mostly for marketing. Although there is an element of logic and organization of models, as with other products, the name is primarily a marketing tool.
The 787-8 emphasizes the number 8. This number has positive connotations in some Asian cultures. Including the two most populous contries in the world, Asia represents a huge market that has been growing rapidly, and this means big opportunities for aircraft manufacturers. As discussed on another question, Airbus and Boeing are both looking to gain orders from this growing market. The launch customer for the 787-8 was a Japanese airline, ANA. Almost a quarter of 787 orders have come directly from airlines in Asia.
Starting with 8 also makes the type seem more established than starting back with -1 or -100, and allows the 747-8 to share the same number to connect the technology shared between the two, mostly in the engines and wings. The 747 connection to Asia is even more apparent than with the 787. Airlines in Asia represent a large portion of past 747 deliveries, which provides an opportunity for them to upgrade to the newest version. Although the launch customers for both cargo and passenger versions are European, Asian customers represent almost half of the orders. Using a single number also differentiates their models from the competition, but also seems to have confused some people that are used to the old convention.
Starting with the 707, Boeing planes started with the -100 and added variants from there. This includes the 727, 737, and 747 as well. The 757 started with the -200 model because this corresponded to the approximate capacity of the 727-200 model it was replacing, which is where they saw the most demand. The 767 started with -100, but this model was never offered, being too close to the 757, so the 767 also starts with -200. The 777 is a similar situation, where a -100 was considered but never offered. The 737 has now run out of numbers, and rather than go up to -10 like the 787 or -1000 like the A350, they chose to go with -7 through -9. This matches the scheme of the other newer models while also relating to the corresponding NG versions of -700 through -900.
The A380 is in a slightly different situation, skipping both type and model numbers to start at A380-800. Although by far the most orders are from one particular airline, customers in Asia still represent almost 20% of the orders. Asia would seem to represent a prime market for a large airplane, with both high traffic routes and long international routes, but like the 747-8 the A380 has not received as many orders as expected. While it's unlikely that either Airbus or Boeing will disclose details of their marketing strategies, it's clear that the number 8 is a positive number in many Asian countries, both manufacturers have chosen to emphasize the number on all of their newest models, and the region represents a very important market for these aircraft.

Interesting. but it all makes sense.  Thanks for that insight!

[citation needed]


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why are regional cruising altitudes higher than those of international much longer flights?
How come, for example, the average cruising altitude of let's say the Westjet Boeing 737-600 from CYWG to CYVR flies at an altitude of 38,000 feet-40,000 feet, yet the Air Transat Airbus 330-200 flying from CYVR to Man EGCC flies between 33,000 feet and 35,000 feet?
Why is the air transat one flies lower when you'd think that with the Vancouver to Manchester route being more of a long-range flight than the Winnipeg to Vancouver one, it'd want to fly above the regional/domestic flights.
Why is this so?
to illustrate, here are flightaware records for two recent flights:
Westjet: https://flightaware.com/live/flight/WJA307/history/20150903/1210Z/CYWG/CYVR
Air Transat: http://flightaware.com/live/flight/TSC284

possible duplicate of Why wasn't MH-17 flying at 33,000ft before it entered Ukrainian airspace?

Note, that if you click through to the altitude graph, the Air Transat 284 usually arrives in Europe at FL390 (39,000 ft).

It seems you looked at flights which had begun shortly before. Since intercontinental flights require a higher fuel fraction to carry enough fuel for the trip, the airplane cannot climb as high initially as one with little fuel onboard. Note that the maximum range of a Boeing 737-700 is 6230 km, while the flight you chose to take as the basis for your question covered only 1936 km. The tanks were probably less than half full, and depending on the passenger load factor, the airplane was probably well below its maximum take-off mass, hence it had no problem to climb so high early in the flight.
Had you included intercontinental flights close to their destination, your question would had been different. Note that TSC284 flew in FL390 shortly before descending. At this point, the tanks held only a fraction of the fuel at take-off, and for a flight of 7526 km it had probably taken off close to its maximum take-off mass. The fuel load of long-range aircraft like the A330-200 can be more than 40% of the take-off mass, so using up most of the initial fuel load can make a lot of difference in the maximum possible flight altitude.

Flight altitudes have relatively little to do with whether a flight is regional or international per se. More important factors include the winds aloft and the individual aircraft capability.
In the case of the Winnipeg to Manchester flight, they were probably using the North Atlantic Track System (NATS). The winds aloft over the North Atlantic are generally out of the west. The routes of the tracks are arranged each day to take advantage of the those winds. The track system puts the eastbound aircraft on tracks and at altitudes that would maximize the tailwinds, and westbound aircraft on tracks and at altitudes that minimize the headwind.
Since the winds aloft in the northern hemisphere are more often than not westerly, the Winnipeg to Vancouver flight might well have been fighting a headwind, but the strongest winds aloft tend to occur in the mid 30s, which can mean that you can lessen the headwind by climbing higher.
Aircraft capability also plays a major role, and aircraft vary widely in what they can do altitude wise. For example, a 747-200 up against its max takeoff weight of 800,000+ lbs can initially climb to only about 31,000 feet (FL310), but towards the end of the flight can reach FL390 and above.

Would the fact that the Winnipeg to Vancouver flight probibly flies over part of the Rockies play much a roll in the altitude choice too?  I know the Vancouver to Manchester does too I believe, the map wouldn't load so I couldn't check.  Iknow things get turbulent over mountains, so planes tend to go higher around those areas too.

@TheCat-alyst For aircraft with normal cruise altitudes above 30,000 feet, I doubt that the terrain altitude below is itself much of a flight planning consideration, but that's not an area of expertise for me. If you're operating within a few thousand feet of the terrain, certainly it would be. Orthographic lifting, though, dies out fairly quickly as you ascend. However, if that lifting (combined with heat and humidity) causes a thunderstorm, you might say the terrain has been a factor.

Regional flights are usually much shorter than the range of the aircraft in use, so the performance argument does explain why regional flights typically fly higher. They start lighter, so they can climb to higher altitude straight away.

If you used typical climb rates how long a ground distance does it take for something like a 747 to reach its max altitude? Do short routes have enough distance to try to climb to their optimal heights & then descend?

@curious_cat You've got two questions there, which I think you should ask as proper questions rather than in a comment. I tried to answer here as a comment, but ran out of room. If you do ask the question about the ground distance, I suggest you use "climb airspeeds" rather than "climb rates" because it's the airspeed rather than the climb rate that is targeted. Also, which max altitude are you referring to? The initial max altitude it's capable of and can go no higher until it burns several thousand pounds of fuel?

@Terry Thanks. I will convert these into a question.